Remarkably little is known about the doctor-elder patient relationship. Older patients present unique clinical challenges; often with multiple condiitons, they present a complex bundle of physical signs, psychosocial symptoms and underlying social challenges. Recent work suggests that how people are actually diagnosed and treated is as much a function of who they are, who is treating them, and where care is received as it is what signs and symptoms are actually presented. This proposal by a multidisciplinary team of social scientists, internists, psychiatrists and statisticians, building on earlier successful work, consists of a factorial experiment to simultaneously estimate the relateive influence of elder patient characteristics (age, gender, race, SES), physician characteristics (gender, race, years since graduation), and features of athe practice setting on clinical decision making (CDM). using professional actors, three common medical conditions (hyperthyroidism, "apathetic" hyperthyroidism, and depression) will be enacted in 6-7 minute videotape scenarios (the average length of a U.S. patient-physician encounter). The tapes will be shown to random samples of practicing internists (from whom most older people receive care) in different practice settings in the greater Boston area who regularly encounter older patients. The conditions are chosen to present ambiguous symptoms, presenting the physicians with considerable latitude for reasonable diagnostic treatment. The innovative experimental design (4 treatment facto[unreadable]s of patient characteristics within incomplete strata defined by 4 physician and practice characteristics) will robustly address a question of clinical and policy importance; which older patients receive what decisions by which physicians in what practice setting? The outcomes of interest include clinical diagnoses, patient workup and treatments recommended. The feasibility of the video-based technique has been thoroughly demonstrated in prior studies. Generalizability of findings is enhanced by employing conditions that are common in older patients and by recruiting female and minority physician-subjects. It is emphasized that this is not a study of the appropriateness of the diagnoses made according to a "gold standard." There are no "correct" decisions; rather, we seek to measure the extent of variability in CDM and identify the specific reasons for such variability.